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4 Amazingly Useful Additions In Python 3.9

Step up your Python knowledge with 4 new statements

Photo by Allef Vinicius on Unsplash
Photo by Allef Vinicius on Unsplash

Python 3.9 has been around since late 2020 and it comes with a bunch of new syntax features and improvements. In this article, we are going to explore a few nice additions which were packed into this version. We will also discuss how to upgrade to Python 3.9 in case you want to.


  1. Merging Dictionaries

As of Python 3.9, you can use the | operator to merge two or more dictionaries together. For duplicate keys the rightmost dictionary takes precedence. This syntactic sugar is part of PEP-584.

Merging two dictionaries using | operator
Merging two dictionaries using | operator
>>> dict1 = {'a': 1, 'b': 2}
>>> dict2 = {'b': 3, 'c': 4, 'd': 5}
>>> dict1 | dict2
{'a': 1, 'b': 3, 'c': 4, 'd': 5}

  1. Updating Dictionaries

Going a step forward, you can also use |= operator to update a dictionary in-place. Essentially a |= b is equivalent to a = a | b but |= won’t return a new dictionary but a will be modified instead. This addition is also part of PEP-584.

Updating a dictionary in-place
Updating a dictionary in-place
>>> dict1 = {'a': 1, 'b': 2}
>>> dict2 = {'b': 3, 'c': 4, 'd': 5}
>>> dict1 |= dict2
>>> dict1
{'a': 1, 'b': 3, 'c': 4, 'd': 5}

  1. Removing a Prefix From Strings

String method removeprefix() can now be used to remove the prefix from strings.

This new additions is part of PEP-616.

Removing prefix from a string
Removing prefix from a string
>>> my_str = 'Title: Hello World'
>>> my_str.removeprefix('Title: ')
Hello World

  1. Removing a Suffix From Strings

The second addition packed into PEP-616 is the removesuffix() string method. Like the previous example, this method can be used to remove the suffix from strings.

Removing a suffix from a string
Removing a suffix from a string
>>> my_str = 'Title: Hello World'
>>> my_str.removesuffix(' Hello World')
Title:

How to Install Python 3.9

In order to install Python 3.9 I would advise you to do so using the official downloads provided in the documentation. There are even a few minor updates to 3.9.0 – make sure to see the latest version(s) available here.

If you are a Windows or OSX user simply download the corresponding file from the first link I provided.

If you are a Linux user you can install it through APT:

$ sudo apt update
$ sudo apt install software-properties-common
$ sudo add-apt-repository ppa:deadsnakes/ppa
$ sudo apt install python3.9

On every platform you should be able to verify that Python 3.9 has been successfully installed by running python --version in the terminal or command-line (depending on your os).


Conclusion

In this article, we discussed a few recent additions in Python 3.9. We showcased how to use | and |= operators to merge and update dictionaries. Additionally, we introduced two new string methods namely removeprefix() and removesuffix() that can be applied over strings to remove the prefix or suffix respectively. Finally, we quickly explored how to install or update (to) Python 3.9.

If you want to learn about more features and improvements that were part of version 3.9, see the official release highlights.


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